The overall objective is to evaluate the efficacy of selected serologic tests as epidemiologic tools for detecting infections of Trichinella spiralis in swine. Such tests must detect infections of varying levels of intensity from at least 17 days postinfection, when infectivity for a new is obtained, through the life span of the swine which may extend through several years. Among the tests to be evaluated are: indirect fluorescent antibody; soluble antigen fluorescent antibody; indirect hemagglutination; Suessenguth-Kline flocculation; charcoal card; counter electrophoresis; and horseradish peroxidase. Other applicable tests may be added during the study. Infected swine will be followed for periods up to 3 years or until antibody titer recedes to a negative level.